The thing that's striking is how that town was dominated by groupthink.
In an instant, they turned on Txato and Bittori as soon as the graffiti came out, including lifelong/best friends, Joxian and Miren. I understand they had to be 100% in support of ETA or else they could be targeted. But Miren is just a miserable woman, bitter and unkind, who made the rest of her family unhappy. Bittori had been nothing but a friend to her but when ETA targeted Bittori's family, Miren abandoned her.
So while she chanted those ETA slogans, I think the way she is depicted has more to do with her character.
That and the Spanish were just brutal to the Basques, so it's not surprising that the populace of that small town would be largely sympathetic. There was definitely an element of fear but also ETA was the enemy of their enemy. The butcher, after he lost his son who was an ETA killer, said what nobody else in the town would say.
I haven't finished it yet but Txato seemed to be a decent and generous man. His only failing maybe was that he didn't get out of that little town when threatened. He thought he could reason with the ETA, which were "exploiters" as one of the characters said, who recruited the sons of Txato and Bittori's neighbors.
There isn't too much overt resentment but Txato and Bittori were obviously wealthy and could afford to get out, even move the business if they had to. The workers at Txato's company either were sympathetic or trying to get the company for themselves, as when they suggested that Bittori transfer the company over to them.
I looked up what a Peseta would be worth in USD back in 1990 and it ranged from 95-105 Pesetas to the Dollar. So Txato paid 2 million Pesetas, which was about $20k and then ETA demanded 25 million Pesetas which would have been over $250k.
There were no allegations that Txato was underpaying or taking advantage of his workers. Instead it seemed his only fault was that he was rich. So the ETA leadership in France may have been the ones targeting the richest businessmen and then ordered local recruits to kill a man whom they'd known all their lives.
Txato said he donated to various causes over the years and his act of kindness by buying that bracelet for Arantxa when she was a little girl was something she remembered all her life.
Txato and Bittori were able to shield Xabi and Nerea, gave them education so that they had options. Joxe Mari seemed like a real believer but didn't seem to be doing anything. Arantxa knew what a screwed up situation her family was, particularly her mother Miren, so she was determined to get the hell out and told Gorka to do the same.